Answer:
31.321 rad/s
Explanation:
L = Tube length
A = Area of tube
= Density of fluid
v = Fluid velocity
m = Mass = 
Centripetal force is given by

Pressure is given by

The angular speed of the tube is 31.321 rad/s
The answers are B, C, E and F.
Atoms from an element is mostly made of protons, neutrons, and electrons. Proton numbers are like a class number for each element. Each element has their own and they're all different. And the number of protons are equal to the number of electrons. Therefore, B is correct.
Isotopes. It's different atoms from a same element that has the same number of protons but different number of neutrons. For example in hydrogen, there's 3 Isotopes for hydrogen. Therefore, C is correct.
Again, proton for the same element is never changed, even if they're different Isotopes. So, E is correct.
Isotopes, again, different elements may have different Isotopes. Some has only 1, others may have a few or more. So, F is correct too.
A this refers to the make up of the soil
Answer:
It's convection
Explanation:
As the hot place transfers heat to the liquid substance, it becomes less dense and rises to the surface given rise for cooler molecules directly above to fall and so undergoes the same circle. In the process the less dense particles are so light that it's swayed into the atmosphere. In the process drying is ensued.